The cancer cell lines, A549 (lung) and MCF-7 (breast) express MUC1, the aptamer MA3 preferentially bound to MUC1-positive but not MUC1-negative cells, suggesting that the MUC1 aptamer may have a potential utility as a targeting ligand for selective delivery of cytotoxic agents to MUC1-expressing tumors including prostate [140]. Here, MUC1 is linked to cancer.